The invention relates to a method for operating a radio communication system, in which network radio devices use radio resources to communicate with subscriber stations.
In radio communication systems, messages, for example with voice information, image information, video information, SMS (Short Message Service), MMS (Multimedia Messaging Service) or other data, are transmitted between a transmitting station and a receiving station over a radio interface using electromagnetic waves. The stations may be here, depending on the specific configuration of the radio communication system, various types of subscriber stations or network radio devices such as repeaters, radio access points or base stations. A mobile radio communication system is composed of mobile radio stations, at least in the case of some of the subscriber stations. Irradiation of the electromagnetic waves is carried out with carrier frequencies which are in the frequency band which is provided for the respective system.
Mobile radio communication systems are often embodied as cellular systems, for example according to the GSM (Global System for Mobile Communication) standard or UMTS (Universal Mobile Telecommunications System) standard, with a network infrastructure composed, for example, of base stations, devices for monitoring and controlling the base stations and further network devices. Apart from these (supralocal) cellular, hierarchical radio networks which are organized over large areas there are also wireless local networks (WLANs, Wireless Local Area Networks) with a generally spatially significantly more strictly limited radio coverage area. Examples of different standards for WLANs are HiperLAN, DECT, IEEE 802.11, Bluetooth and WATM.
The access of subscriber stations to the common transmission medium is regulated by multiple access methods/multiplex methods (MA) in radio communication systems. In these multiple access operations, the radio resources can be divided in the time domain (Time Division Multiple Access, TDMA), in the frequency domain (Frequency Division Multiple Access, FDMA), in the code domain (Code Division Multiple Access, CDMA) or in the spatial domain (Space Division Multiple Access, SDMA). Combinations of multiple access methods are also possible, for example combination of a frequency domain multiple access method with a code domain multiple access method. In order to be able to achieve the most efficient radio transmission possible, the entire available frequency band can be divided into a plurality of subbands (multi-carrier methods). The idea on which the multi-carrier systems are based is to convert the initial problem of the transmission of a broadband signal into the transmission of a plurality of narrowband signals. An example of a multi-carrier transmission method is OFDM (Orthogonal Frequency Division Multiplexing).